SLROC Forum

Hi

Anyone have any advice on what split charge system to use for winching ?? and how they work.

cheers
Sam

Hi
    I don't use a split charge for my winch set up, I have twin batteries wired in prallel. This is my engine starting set up, I only use the winch with the engine running with the winch wired through its own master cut off switch.
I do have a split charge which is for the two batteries in the camper body, the split charge is set up to handle the maximum output of the alternator, just incase you completely flatten the secondary battery. I have a 100amp alternator so I have a 120 amp relay utilising 266/0.30 cable(135amp). The relay trigger(pin 86) is wired to the brown/yellow(alternator warning light wire which provides a positive feed with the alternator charging) with the relay winding(pin 85) wired directly to earth. On this relay pins 30 and 87 are studs and nuts to handle the current, pin 30 is heavy positive(266/0.30 cable) wired to the main battery positive with pin 87 coming from the relay to the positive on the secondary battery. I run unfused on this setup but you can add a 120 amp maxi fuse for protection while still allowing a full 100 amp to flow to a flat battery.

The alternative way to wire the split charge relay is pin 86 wired to an ignition feed with pin 85 (relay winding negative) wired to the starter motor. You add the wire to the bottom large stud on the starter solenoid, the one with the short cable that disappears inside the starter motor.
This earths the relay windings through the starter but when the engine is cranking the split charge relay switches off as the earth is lost until the starter stops operating.
My Land Rover has a serpentine 3.9 v8 in it and I'm in the process of adding twin alternators, one to charge the vehicles two batteries and the other to charge the two batteries in the camper body.

Hope this helps,
                       Stevie.

For short term occasional use -  a simple recovery, shifting a fallen tree etc, you probably don't need a split charge & twin battery system at all.  I run my winch straight off the one single 072 battery that's also powering everything else. Keep the engine running throughout and its good to go for most normal tasks, its been fine for an hour or so's intermittent tree hauling fr'instance.

If you are planning on lots of winch use - pay and play days in the deep clag, or heavy repeated work, or just want to be absolutely sure of getting started again then follow Steves advice - but don't feel you have to add a second battery "just because"

G. 


 

It was something I always meant to do but never got round to. My winch has been extensively used with just a single battery and the engine running and never caused a problem, I cant see that you would use it without the engine running anyway would you?

landrover list a winch battery as an option for defenders, it isnt a second battery just a bigger one, actually the same as a standard td5 disco battery whatever that number is.
i do lots of recovery work running two winches front and rear and my experience of split charge etc is they are bad news.
i run a matched pair of batteries kn parallel  and have done for years in the defender. my td5 disco ran its standard battery with warn winch no problem

Depends what you want to do, for winch challenge events it is a good idea due to the constant drain, (as set up above) for a "normal" vehicle at pay and play events a single battery (especially in a diesel vehicle) will do, petrol engined vehicles tend to have a smaller battery, you could either fit a bigger one or go the split charge route.

In either case the engine would always be running as electric winches will drain the battery quicker than the alternater can top it up.

If you want a simple wiring system look at a split charge diode. It coms as a complete unit, wire the start battery to terminal 1. Alternator to terminal 2. Winch (service) battery to to terminal 3.
It will send out the charge to either battery, but they will never link together. So if you are winching faster than charge, then it won't effect your starter battery.
Again make sure it can handle the amps of your alternator.

Something like Mastervolt Battery Isolator Type BI-1202

The biggest problem with split chargers is that the relay that connects the second battery to the charging system needs to be able to cope with the current draw when the "auxiliary" devices are being used.

Example: lets say you want to run a fridge and a light and a radio in the car, and not worry about them draining your starting battery.
All together, they'll probably draw about 30 amps, so your average relay will cope with all of that.

If you assume that the relay only kicks in (connects the batteries) when the alternator is putting out 13V plus, then the relay will never be asked to cope with the loads-of-amps needed to start the car.
This solution is easy, and pertty much any relay can do the job.

The next step up is to find some kind of commercial split-charge ... I had one that could cope with 70 amps.
This was fine, and it coped well with all the weird electronics I had in the car, but when I used the winch, it wanted 120+ amps... which it drew from both batteries.... and the relay kinda melted (oops)

Your next step is to find a winch-relay, and use a split-charge relay to trip THAT, which then joins the two batteries.... and THAT can cope with the current flow.

Your third option is to go to dual alternators.... and charge the two batteries independently.... and use a switch to positive select joining the two systems together...

Hi

Thanks for the reply's ,think I will just go with 2 batteries as it wont be used every day.

thanks again

cheers
Sam

Most sailing yachts of any size have two batteries (or more) in parallel, with one of them reserved for engine starting only, the other(s) being for powering lights, navigation electronics, etc., etc., when under sail or at anchor. Some boats have split charging but most don't and I've always found that a heavy battery selector switch allowing for No 1, Nos 1&2 and No 2 batteries to be selected is adequate. Engine starts are done using No 1 or Nos 1&2. With the engine running, 1&2 are always selected and with the engine stopped, 2 is used.

If you wanted to play safe, you could rig up something along those lines such that one battery is always isolated and fully charged when you're using the other to power the winch.

This sort of thing does the job:
http://www.ebay.co.uk/itm/SEAFLO-MARINE-HEAVY-DUTY-BATTERY-SELECTOR-SWITCH-Yacht-BOAT-4-x-4-MOTORHOME-/181429659556?pt=UK_CarsParts_Vehicles_BoatEquipment_Accessories_SM&hash=item2a3e0ce7a4